My guess is the default kernel is too new for zfs to build.
Maybe i should use an older kernel and pin it down.
No idea how i can do this ...
maybe install linux-lts ? (for now it(s from the branch 6.6.xxx)
Sometimes you can find commits or use git version of openzfs that may work for newer kernels. https://github.com/openzfs/zfs is the repo. Also there is https://github.com/archzfs/archzfs where you can use as a repo to install kernels from that has zfs support etc.